1. Field of the Invention
The present invention relates to a multilayer circuit substrate obtained by alternately stacking conductor layers and insulator layers, and more particularly, relates to a structure suitable for transmission of high frequency signals.
2. Description of Related Art
Mobile phones and other electronic devices are examples of usages of this type of multilayer circuit substrate. However, recently there has been demand for thinner and denser multilayer circuit substrates following the demand for smaller electronic devices with more functions. In order to respond to this demand there has been an emergence of component embedded circuit substrates in which various types of electronic components such as capacitors are embedded into a multilayer circuit substrate (see Patent Document 1). Patent Document 1 discloses a multilayer circuit substrate having a conductor layer formed of metal thicker than the other conductor layers and arranged in the inner layer thereof as the core layer to improve noise resistance and strength of electronic components. The electronic components are arranged in through-holes formed in the core layer. Furthermore, conductor layers and insulator layers are formed on the top surface and bottom surface of the core layer.